Even more surprising, all three acupuncture techniques tested -- including a "sham" technique with toothpicks and no skin puncturing -- worked better than the usual care given for the problem.

"Acupuncture-like treatments had a positive effect overall on people's chronic back pain," says study researcher Dan Cherkin, PhD, a senior investigator at Group Health Center for Health Studies in Seattle. "It didn't matter if you inserted the needle or superficially poked [the skin]."

That finding, Cherkin says, leads to more speculation about how the centuries-old technique actually works.

The study is published in the Archives of Internal Medicine.

Cherkin and colleagues assigned 638 men and women with chronic low back pain who had never before had acupuncture to one of four groups:

• Individualized acupuncture group. Patients received acupuncture treatment based on a customized prescription for acupuncture points.

• Standardized acupuncture group. Patients received an acupuncture treatment considered effective by experts for chronic low back pain.

• Simulated acupuncture group. Patients received a treatment that mimics needle acupuncture but used a toothpick in a needle guide tube without penetrating the skin.

• Usual care group. Patients continued whatever they were doing, such as taking pain medicine or undergoing physical therapy.

Acupuncture treatments were given two times a week for three weeks, then once a week for four weeks. The researchers measured back pain-related problems and dysfunction at eight weeks, a half year, and one year after the treatments.

Participants in the trial, funded by the National Institutes of Health, were told only that the researchers were comparing three different methods of stimulating acupuncture points.

Acupuncture vs. 'Usual Care'

"The individualized acupuncture did not provide any benefit over the standardized acupuncture," Cherkin tells WebMD. "The simulated acupuncture, which did stimulate the standardized points, also had the same effect. All three did better than usual care."

Those who got any of the acupuncture treatments were more likely than those getting usual care to have a "meaningful" improvement in the dysfunction scale, which reflects the ability to engage in activities of daily living. Overall, 60% of the acupuncture-treated patients, but just 39% of the usual-care group patients, had meaningful improvements in dysfunction, the researchers found.

That translated to those in the acupuncture group being able to do more daily activities, such as going to social functions or performing household tasks, Cherkin tells WebMD.

After a year, those in the acupuncture groups were also more likely than the usual-care group to continue to have improvement in dysfunction, with up to 65% of the acupuncture-treated patients but just 50% of the usual-care patients still reporting improvements. But the improvement waned over time.

The finding that the simulated acupuncture was as good as needle acupuncture is puzzling, Cherkin admits. "What we can say is, it is not essential to achieve a benefit to insert the needle through the skin," he says.

Why this is so is not known, he says. "One possibility is there is a physiological chain of events that occurs when you insert a needle or just stimulate the skin superficially. They may or may not be the same."

Another possibility, he says, is "believing you are getting a treatment that will help your back pain" helps it.

And, he adds, not all participants benefited from the acupuncture, whatever the form. Still, he says, "acupuncture is a reasonable option" for those with low back pain. Americans spend at least $37 billion a year for medical care for back pain, Cherkin notes in his report.

'Acupuncture Can Help'

"Although this study has shed some light [on back pain treatment], it is also confusing, I think," says Arya Nick Shamie, MD, associate professor of spine surgery at the University of California David Geffen School of Medicine and a spokesman for the American Academy of Orthopaedic Surgeons.

"For the most part, acupuncture is very safe," says Shamie, who has recommended it to his patients with chronic back pain. However, he adds, "this paper has confused the issue even further as to how acupuncture works." Even so, he says, "what it does show is acupuncture can help patients."

The good results with the "toothpick" acupuncture may very well be a placebo effect, Shamie says. "Even going and talking to your doctor could have a strong, positive effect on your health," he says. "When people have chronic illness, they want to feel that someone cares for them, and that basically unloads the mind of the burden of disease."

His caveat: "Chronic back pain should be evaluated by your physician or a specialist," he says, to rule out any serious underlying medical problems.